Warren Buffett has done it again. In a recent $1 million wager for charity, Buffett declared that he could achieve better returns by investing in a S&P 500 passive index fund than a group of hedge fund managers. The bet will be collected later on this year; Buffett has proven once more that you can take his investment advice to the bank.

While Buffett’s position in theory is sound; the strategy he purports is questionable. So says Timothy Armour, Chairman and Chief Executive Officer of Capital Group in a recent CNBC commentary. Armour acknowledges that no one better delivers the message that Americans need to save more for retirement than Buffet, but in this commentary he wanted to add his own perspective.

He first warns consumers to be wary of product labels. Armour, a graduate of Middlebury College with a Bachelor of Science degree, believes that mutual funds have a history of low long term returns because of management fees and excessive trading. Because the cost and risk of passive index investments are underestimated and unknown, Armour believes the focus should be on delivering good returns on long-term investments at a low cost. According to Tim Armour, it’s time to challenge passive index returns as a safe way to a secure retirement because they don’t provide a safety net against down markets.

Armour, however, is encouraged by Donald Trump’s unexpected election upset. Trump’s willingness to change the way things are done in Washington is seen by Armour as an opportunity to bring about changes that will impact investors’ portfolios.